In recent years, the demand for coffee has been increasing as living standards have risen with increasing income, and coffee manufacturers and coffee shops, which sell coffee based beverages, are gradually proliferating.
In particular, espresso coffee using coffee beans has come to be widely known as consumers become increasingly knowledgeable about coffee flavor and fragrance. Espresso coffee is a thick coffee liquid extracted by supplying high-pressure and high-temperature water to ground coffee beans.
In addition, as an example of a coffee having mild flavor and fragrance, Americano coffee, is made by adding hot water to espresso coffee. As described above, espresso coffee is the basic ingredient of various kinds of coffee based beverages.
FIG. 1 is a view illustrating a process of extracting espresso coffee according to the related art.
The process of extracting espresso coffee according to the related art will be described below with reference to FIG. 1.
To extract espresso coffee according to the related art, hot water is supplied to pass through a coffee extractor 10, in which ground coffee beans are accommodated, from the bottom to the top thereof using a transport pump so that the ground coffee beans are pressurized by the hot water, whereby a coffee liquid is extracted.
When espresso coffee is extracted according to the related art as described above, the ground coffee beans accumulate on the upper section of the coffee extractor 10 by the movement of the hot water. When a large amount of fine particulates having a small size of the ground coffee beans is distributed in a specific region inside the coffee extractor 10, flow resistance, which prevents the movement of the hot water, is increased, which causes pressure to be concentrated on a specific region inside the coffee extractor 10. Due to this, the distribution of pressure inside the coffee extractor 10 becomes unbalanced, which makes it difficult to extract a coffee liquid and reduces the yield thereof.
In addition, the coffee liquid extracted from the espresso coffee extractor 10 according to the related art contains bubbles, and the bubbles contain aroma ingredients that convey a unique coffee fragrance. However, because the bubbles generated in the process of extracting the coffee liquid are separated and discharged in the related art, there is a problem in that the extracted coffee liquid loses a lot of unique coffee fragrance.